A deep ultraviolet laser light with a wavelength of 200 nm or less is known to be applied to exposure devices, inspection devices, therapy devices, and so on. A variety of configurations of an ultraviolet laser device for use in these devices have been proposed. For example, an ultraviolet laser device, in which, a seed light of an infrared wavelength emitted from a laser light source is amplified by an erbium doped fiber amplifier (EDFA), then the amplified infrared laser light is sequentially wavelength-converted through a plurality of wavelength conversion elements, for outputting a deep ultraviolet laser light with a wavelength of 200 nm or less, is known (refer to Patent Document #1 and Patent document #2). An ultraviolet laser device with this kind of configuration is an easily handled, small-scale, and all-solid ultraviolet laser device.